[bigsix]

  All credits shall be addressed to DX90 hardware developers - they really have done a great job! I just corrected mistakes made by software engineers. I even can't call them bugs, because, formally, all is correct... but both hardware and software skills are required to analyse and realise how they influence each other and then tune them up.

 
Also, advocating iBasso programmers, please note that most of the time they listen debug versions of the software, that produce much more load on CPU, so that they had less chances to catch the problem.

 
Wow, this FW version sounds fabulous! Although you modestly give all credit to the iBasso team, you have put extra polish on what was already a fine product. Thank you so much for your hard work!

 

[Robseth]

@Lurker0 is stock firmware also bit perfect? Or is it something you did and is only in your mod?

 

[Lurker0]

  @Lurker0 is stock firmware also bit perfect?

Yes! You can read full list of changes made by me to realize that I made no changes to the iBasso software itself!

 

[llcook51]

I have the DX-50 but it's touch screen is too sensitive for my "club" fingers. Is the DX-90 screen significantly less sensitive?

 

[intlsubband]

I have 3 different batteries - the stock, a Samsung, and another generic one. I can't tell any sound difference.
 
So, is there an alternate back cover available for the DX90? I bought a 4800 battery and it came with a replacement Samsung Galaxi back panel, I would like to use it with the DX90 but I don't like the idea of holding it in place only with the silicone case and no back panel.

 

[jamato8]

The silicon case holds it in place just fine. I have done it for a long time, zero problems. 
 
I use the Samsung and do hear a difference, an improvement. I also have 2 Samsung batteries I soldered in series and there is a little improvement with that as well as there is a lower ESR so better current availability and a more stable voltage. 

 

[hyper8]

  I have 3 different batteries - the stock, a Samsung, and another generic one. I can't tell any sound difference.
 
So, is there an alternate back cover available for the DX90? I bought a 4800 battery and it came with a replacement Samsung Galaxi back panel, I would like to use it with the DX90 but I don't like the idea of holding it in place only with the silicone case and no back panel.

I forgot what user was using the Kinps battery,but he had a back cover

 

[bimadz]

  Pretty looking, high performance DX90 firmware based on 2.1.0, International version
Brief description:

• Incorporates all the changes made in this firmware version.
• CPU is always working at the highest performance.

 
What does it mean?
Changes in the CPU working frequency during audio playback affects the stability of the power source and temperature, probably, also the stability of the sound stream from CPU to DAC. So, stable CPU speed also means stable power and temperature of other components: DAC, clock generator, op-amps. Stability of the environment parameters of the DAC and clock generator also leads to lower jitter.
 
I will not provide any comments on how it changes the sound. I only want to mention that some people have tested this firmware without communication with each other, and all of them provided very similar feedbacks, similar also to my personal opinion. The feedbacks only differ in how the changes are noticeable, and do testers like them or not.
 
Required comments
Obviously, this firmware is influenced by burn-in effect: from the cold start, it takes some minutes to achieve the working stable conditions. Then, it works in the most clean sound playback conditions that can be reached now.
 
Some people may feel that with this firmware the sound volume level is less than with any other firmware version. The main reason is that, due to minimized distortions, the level of comfortable volume is higher. Meaning, this difference has psychological roots.
 
The difference is less notable on materials that require high CPU load (DSD, 24/192).
 
Nobody noticed any reduce in the battery lasting time.
 
Download link
 
Detailed description
The OS kernel supports the following CPU performance governors:

• performance (highest frequency)
• ondemand (frequency depends on CPU load; fast raise, fast scale down)
• interactive (frequency depends on CPU load; fast raise, slow scale down)
• powersave (lowest frequency)

 
The CPU in DX90 supports only two frequencies: 312 and 504MHz. It means, it only can be switched between these two frequencies. The power consumptions at these frequencies differ in around 2 times, and power dissipation at the high speed is notably more than at the low speed.
 
I've found evidence in MandoPlayer and other components, that it was an intention to switch to performance mode during playback, and to ondemand mode during pauses, but it does not work such a way. Instead, the CPU works in interactive mode all the time. This firmware turns the performance mode at the early boot step, and then prevents changing the policy and CPU frequency, just in case. So, I can claim that with this firmware DX90 sounds exactly as it was intended by iBasso developers.
 
I've tested the permanent powersave mode as well. It does not add to the sound, probably, because the absolute difference in power consumption between powersave and performance is not so big. But situations when CPU speed is not enough are fatal: the player may hang or reboot.
 
More required comments
This firmware, like the previous firmware, is bit perfect. It means, with EQ turned off, the sound data is not affected by the software, and is transferred to the DAC exactly as it is.
 
Also, no a part of Android sound path (including audio policy configuration file and corresponding libraries) is used or ever loaded in this firmware.

can someone provide the alternative link? it seems like the download link above is dead.

 

[jamato8]

I would guess it was only allowed a certain number of downloads for a set time. 

 

[nmatheis]

Maybe someone could mirror it on Dropbox?

 

[T.R.A.N.C.E.]

Might as well just keep things simple and use Lurkers new 2.1 

 

[nakedtoes]

  Pretty looking, high performance DX90 firmware based on 2.1.0, International version
Brief description:

• Incorporates all the changes made in this firmware version.
• CPU is always working at the highest performance.

 
What does it mean?
Changes in the CPU working frequency during audio playback affects the stability of the power source and temperature, probably, also the stability of the sound stream from CPU to DAC. So, stable CPU speed also means stable power and temperature of other components: DAC, clock generator, op-amps. Stability of the environment parameters of the DAC and clock generator also leads to lower jitter.
 
I will not provide any comments on how it changes the sound. I only want to mention that some people have tested this firmware without communication with each other, and all of them provided very similar feedbacks, similar also to my personal opinion. The feedbacks only differ in how the changes are noticeable, and do testers like them or not.
 
Required comments
Obviously, this firmware is influenced by burn-in effect: from the cold start, it takes some minutes to achieve the working stable conditions. Then, it works in the most clean sound playback conditions that can be reached now.
 
Some people may feel that with this firmware the sound volume level is less than with any other firmware version. The main reason is that, due to minimized distortions, the level of comfortable volume is higher. Meaning, this difference has psychological roots.
 
The difference is less notable on materials that require high CPU load (DSD, 24/192).
 
Nobody noticed any reduce in the battery lasting time.
 
Download link
 
Detailed description
The OS kernel supports the following CPU performance governors:

• performance (highest frequency)
• ondemand (frequency depends on CPU load; fast raise, fast scale down)
• interactive (frequency depends on CPU load; fast raise, slow scale down)
• powersave (lowest frequency)

 
The CPU in DX90 supports only two frequencies: 312 and 504MHz. It means, it only can be switched between these two frequencies. The power consumptions at these frequencies differ in around 2 times, and power dissipation at the high speed is notably more than at the low speed.
 
I've found evidence in MandoPlayer and other components, that it was an intention to switch to performance mode during playback, and to ondemand mode during pauses, but it does not work such a way. Instead, the CPU works in interactive mode all the time. This firmware turns the performance mode at the early boot step, and then prevents changing the policy and CPU frequency, just in case. So, I can claim that with this firmware DX90 sounds exactly as it was intended by iBasso developers.
 
I've tested the permanent powersave mode as well. It does not add to the sound, probably, because the absolute difference in power consumption between powersave and performance is not so big. But situations when CPU speed is not enough are fatal: the player may hang or reboot.
 
More required comments
This firmware, like the previous firmware, is bit perfect. It means, with EQ turned off, the sound data is not affected by the software, and is transferred to the DAC exactly as it is.
 
Also, no a part of Android sound path (including audio policy configuration file and corresponding libraries) is used or ever loaded in this firmware.

thanks lurker... is this the same as the previous international version firmware u posted earlier or is the newer version?

 

[nakedtoes]

anyone can upload the new lurker firmware to share thanks

 

[wizard327]

Tried to download Lurker's 2.1 FW but got a message that the link is temporarily disabled since it is generating a lot of traffic. Maybe somebody who has already downloaded this latest FW can upload somewhere or here? Thanks guys

 

[Wyd4]

Any chance someone could link me a quality battery replacement they have been using with this? Only needs to fit under silicone or leather case. Not too worried whether the rear housing fits but if so bonus. I am finding the battery life to be less than the quoted 8 hours.

Also I would be more than happy to setup a folder on my Google drive for lurker, though I am not sure how much traffic they allow.